Passenger compartment heating and cooling are provided in most automobiles. In internal combustion engines of automobiles, an engine driven compressor runs a vapor compression air conditioning system for summer operation. In the winter, waste heat of combustion is used for heating the passenger compartment. In future vehicles designed to decrease automobile emissions, this source of propulsion energy is commonly an electric storage device, such as a battery. The amount of energy that can be stored in the currently available battery is limited, therefore there is a need to minimize the use of stored energy for other uses such as passenger thermal comfort.
It is has been proposed to use heat pump switchable systems on electric vehicles wherein refrigerant flow direction is reversible. Outside of vehicle applications, it has been determined that musty odors exist as a result of organism growth on the evaporator in the heat pump system after air conditioning use, as suggested in U.S. Pat. No. 3,762,178, issued Oct. 2, 1973 in the name of Yamada et al. The patent discloses a coolant apparatus for cooling the interior of a room in which a blower is started after a time delay from starting the evaporator to force cooled air into the room.
U.S. Pat. No. 4,094,166, issued Jun. 13, 1978 in the name of Jerles discloses an air conditioning control system which eliminates the odor problem. The patent discloses operating the evaporator fan after the compressor and the condenser fan have stopped to continue cooling. The actuation of the evaporator fan is based on an increase in efficiency rather than preventing odor.